Heh, so now who's going to be adventurous and try to bend and fit this in with two OPA627's?

I have a similar idea, but instead I was trying to make it into a rollable SOIC socket. However, it didn't materialize at the end because there is simple no space inside the X3. Anything taller than a typical SO8 opamp will hit the battery.

Quote:

Originally Posted by AmberOzL

ClieOS, at your signature it says almost time to leave with very small letters. Does it mean soon you will close head-fi account? I hope not

I'll remain a member, but mostly as a lurker.

Quote:

Originally Posted by phantompersona

Can I send a x3 for you to mod?I'll gladly pay you

Sorry, I don't have enough confidence in my DIY skill to take on another person's X3.

FiiO R&D team suggested ADA4896 as good candidate for modding, as it is also more neutral than stock and still does rail-to-rail. I am going to throw in AD8066 as an alternative as well. It is more aggressive and bright compared to AD8620, but it is rail-to-rail so you will keep the dynamic.

FiiO R&D team suggested ADA4896 as good candidate for modding, as it is also more neutral than stock and still does rail-to-rail. I am going to throw in AD8066 as an alternative as well. It is more aggressive and bright compared to AD8620, but it is rail-to-rail so you will keep the dynamic.

I think, the higher the slew rate, the faster or more detailed the sound is.

I think, the higher the slew rate, the faster or more detailed the sound is.

Why rail to rail?

Not so much about detail sound - you want it not to be slew rate limited, but excessively fast slew rate doesn't do you much good. That is, you need it to be fast enough for music. Faster doesn't make much sense since we don't need it to be fast enough for ultrasound range and slower is definitely not going to be good.

Rail-to-rail means the output of the opamp can swing very close to the supply voltage rail. Supply voltage in X3 is around +/-5V ~ +/-5.5V. So in theory, the stock AD8397's output can swing around +/- 5V (which is already more than X3's output volume in high gain) in full without clipping or inducing any noticeable noise. AD8620 on the other hand isn't rail-to-rail, so it will swing in much smaller range. If you have low sensitivity load that requires you to push for very high volume, AD8620 will begin to clip and distort. That's the downside of using AD8620 as it doesn't do rail-to-rail and doesn't have that much current output to deal with low sensitivity and low impedance load. But given those are more extreme cases, and usually not the kind of headphones I will use portably, AD8620 will still serve my purpose. Having a rail-to-rail opamp just gives you a bit more versatility when it comes to different headphone load. AD8397 in this case is actually technically a really good all-in-one solution. I would have kept it if not fro the obvious warmness. The way I see it is, if I really want to use a difficult to drive headphone, I'll just carry an amp with me. That's why AD8620 suits me just fine.

Not so much about detail sound - you want it not to be slew rate limited, but excessively fast slew rate doesn't do you much good. That is, you need it to be fast enough for music. Faster doesn't make much sense since we don't need it to be fast enough for ultrasound range and slower is definitely not going to be good.

Rail-to-rail means the output of the opamp can swing very close to the supply voltage rail. Supply voltage in X3 is around +/-5V ~ +/-5.5V. So in theory, the stock AD8397's output can swing around +/- 5V (which is already more than X3's output volume in high gain) in full without clipping or inducing any noticeable noise. AD8620 on the other hand isn't rail-to-rail, so it will swing in much smaller range. If you have low sensitivity load that requires you to push for very high volume, AD8620 will begin to clip and distort. That's the downside of using AD8620 as it doesn't do rail-to-rail and doesn't have that much current output to deal with low sensitivity and low impedance load. But given those are more extreme cases, and usually not the kind of headphones I will use portably, AD8620 will still serve my purpose. Having a rail-to-rail opamp just gives you a bit more versatility when it comes to different headphone load. AD8397 in this case is actually technically a really good all-in-one solution. I would have kept it if not fro the obvious warmness. The way I see it is, if I really want to use a difficult to drive headphone, I'll just carry an amp with me. That's why AD8620 suits me just fine.

Thank you for the input. I always read these opamp specific designations and do not really understand them in connection with headphone audio.

ClieOS, your modified FiiO X3 with what you are listening to headphones?

I am not sure what your question is. Are you asking which headphone I mod'ed my X3 for? If that's the question - I didn't mod the X3 with any particular headphone in mind. I have quite a large collection and don't usually listen to just one set. But most of them are not very difficult to drive so they should work on the mod'ed X3 just fine.

ClieOS, Excuse me for my English. What headphones do you use? Together with FiiO X3?

Check out my profile to see what headphone I have. I really don't stick to just a pair of headphone. Some of the headphone I use frequently with X3 include HiFiman RE0, Etymotic ER4S, Sony MDR-1R, Beyerdynamic DT1350, LEAR LCM-5, JVC FXZ200, Sennheiser MX985, Blox TM7/ANV3, Denon C300 - just to name a few.

Have you ever heard the AD835? I've seen at least one guy on HF preferring it to at least a dozen other op amps. He was talking about CMOY though.

Going by the specs it's rail-to-rail too, so I'm thinking of trying it, once I get my X3.

It is single channel so it is not suitable for X3 at all. It is also not rail-to-rail, according to the datasheet (typical +/-2.5V swing from +/-5V supply, so it is 50%). I don't even think it is classified as opamp. It is just not something I will use as opamp replacement without carefully looking into the circuit design it will be sitting in.

It is single channel so it is not suitable for X3 at all. It is also not rail-to-rail, according to the datasheet (typical +/-2.5V swing from +/-5V supply, so it is 50%). I don't even think it is classified as opamp. It is just not something I will use as opamp replacement without carefully looking into the circuit design it will be sitting in.

Wait, are you sure it is AD835 and not AD827?

Man, this guywas talking about AD825. Why was I thinking about 835 all this time? Sorry for the confusion

Well, maybe the AD827 is the dual op-amp closest to the AD825. But obviously I don't know what I'm talking about